Evaluation of laser hazards to the eye and the skin.

Abstract

Abstract Laser eye and skin hazards are evaluated by comparing direct-exposure intensity levels on the surface of the eye or skin to exposure guidelines equal to (a) threshold effect levels where the skin or cornea is affected and (b) conservatively safe levels based on worst case assumptions where the retina is affected. Equations are presented for calculating the exposure intensity when the laser beam parameters and the range are known. Intensity amplification factors of the eye are indicated for the three cases encountered in practice: (a) where simple geometric optics apply, (b) where the laser beam divergence angle is limiting, and (c) where Fraunhofer diffraction effects are limiting. Diffraction effects predict the maximum eye intensity amplification and hence define the worst case for retinal exposure. The resultant exposure guidelines are summarized, and estimates are made of the associated safety factors. These exposure guidelines quickly identify problem areas that may require more complicated ...